Method for correcting offset in a magnetic disk including apparent offtrack cancellation

Abstract

A method for writing a servo pattern in a hard disk device comprises the steps of reproducing a first servo signal from a servo surface, recording a second servo pattern on a recording surface using a data head by controlling the data head on a track defined on the recording surface, reproducing a second servo signal from the recording surface in response to the second servo pattern recorded thereon using the data head, detecting an off-track of the data head with respect to the predetermined track on the recording surface; shifting the data head in a radial direction of the recording surface with an offset such that the off-track is canceled, and recording a third servo pattern on the recording surface using the data head at a position determined in the step of shifting the data head.

What is claimed is: 
     
       1. A method for writing a servo pattern in an information storage device, said information storage device including a servo surface having a first servo pattern for controlling head tracking stored thereupon; a data surface; a servo head for reproducing first servo signals from said servo surface; a data head for reproducing data signals and second servo signals from said data surface; a head position detection unit for detecting positioning of said servo head based upon said first servo signals; and a data head control unit for controlling positioning of said data head based upon positioning of said servo head; said method comprising the steps of: recording a second servo pattern for controlling head tracking on said data surface by said data head while controlling the positioning of said data head based upon the positioning of said servo head;   reproducing a second servo signal from said data surface using said data head in response to said second servo pattern while controlling the positioning of said data head based upon the positioning of said servo head;   detecting a deviation in said second servo signal that indicates an apparent off-track of said data head from said track while controlling the positioning of said data head based upon the positioning of said servo head; and   re-recording said second servo pattern on said data surface without re-recording data information while shifting said data head in a radial direction of said data surface with an offset to cancel said apparent off-track.   
     
     
       2. A method as claimed in claim 1, wherein said step of reproducing said second servo signal, said step of detecting a deviation in said second servo signal and said step of re-recording said second servo pattern are conducted in a substantially stabilized temperature environment. 
     
     
       3. A method as claimed in claim 1, wherein said step of detecting the deviation in said second servo signal comprises a step of detecting a direction of shifting of said data head for reducing said apparent off-track, and said step of re-recording said second servo pattern is conducted while shifting said data head in said direction based upon said position of said servo head. 
     
     
       4. A method as claimed in claim 1, wherein said step of detecting the deviation in said second servo signal and said step of re-recording said second servo pattern are repeated one or more times. 
     
     
       5. A method as claimed in claim 3, wherein said step of detecting the deviation in said second servo signal and said step of re-recording said second servo pattern are repeated until a direction of shifting of said data head for reducing said apparent off-track is reversed.